Amazhomidia, Cipola, Nikolas Gioia, Morais, José Wellington De & Bellini, Bruno Cavalcante, 2016

Cipola, Nikolas Gioia, Morais, José Wellington De & Bellini, Bruno Cavalcante, 2016, A new genus of Entomobryinae (Collembola, Entomobryidae) from Brazilian Amazon with body scales and dental spines, Zootaxa 4105 (3), pp. 261-273 : 262-264

Amazhomidia gen. nov. Cipola & Bellini

Type species. Amazhomidia ducke sp. nov.

Diagnosis of genus. Heavily striate apically pointed scales on dorsal head, thorax and abdomen ( Fig. 2 ), absent on antennae, legs, collophore and furcula; antennae with 4 segments, Ant. IV annulate, without apical bulb ( Figs 10 , 15 ); eyes 8+8; prelabral chaetae bifurcate; labral papillae absent ( Figs 13–14 ); cephalic groove with scale-like chaetae ( Figs 3 , 20 ); macrochaetotaxy relatively dense; Abd. II–IV bothriotrichal formula 2, 3, 2; accessory microchaetae of bothriotrichal complexes elongated; ms and sens formula of Th. II–Abd. V as 1, 0| 1, 0, 1, 0, 0 and 2, 2| 1, 1, 2, 14, 3, respectively ( Figs 13 , 22–28 ); Abd. IV well developed, several times the length of Abd. III in the midline ( Figs 1 , 26–27 ); unguis with 3 inner (two basal paired and one median unpaired) and 2 large laterodorsal teeth; unguiculi I–II truncate, unguiculus III acuminate, with small external basal small tooth; tenent hairs capitate, slightly longer than unguis ( Figs 33–35 ); tenaculum with 4+4 teeth and one basal, multi-laterally ciliate chaetae ( Fig. 37 ); male genital plate papillate, surrounded by ciliate chaetae ( Fig. 38 ); manubrium lateral face with long distal mac ( Fig. 40 ); dental spines present and striated; mucro bidentate with basal spine reaching subapical tooth ( Figs 41–42 ; Tab. 1 ).

Etymology. The genus was named after the region in which is was collected and because it is most similar to Sinhomidia in morphology.

Remarks. Amazhomidia gen. nov. is given generic status within the group of other Homidia -like genera because of a combination of characters. These are prelabral chaetae bifurcate, labial chaetae ciliated (except R sometimes smooth or absent), manubrium with long distal mac, and Abd. IV with two transverse rows of mac on anterior central region ( Figs 3 , 14 , 19 , 27 , 40 ). These features combined with body scales, cephalic groove with very distinct scale-like chaetae and one row of ciliate spines on dens differ from all other genera of Entomobryinae .

Amazhomidia gen. nov. is most similar to Sinhomidia by the presence of apically pointed scales on dorsal body, Ant. IV annulated, labral papillae absent, tenent hairs capitate, dental spines present and, especially, by dental scales absent ( Zhang et al. 2009). The new genus also resembles the unscaled genus Homidia (Entomobryinae) in cephalic groove with scale-like chaetae, dorsal macrochaetotaxy, dental spines, and structure of unguis, unguiculus and mucro ( Chen & Li 1997, 1999, Wang & Chen 2001, Jia et al. 2005, Zhang et al. 2009, Shi et al. 2010, Pan & Shi 2015; Pan et al. 2015). Amazhomidia gen. nov. can be separated from these other genera by presence of body scales (absent in Homidia ), Ant. IV without apical bulb (present in Homidia and Sinhomidia ), prelabral chaetae bifurcate (simple in Homidia and Sinhomidia ), labial chaetae m and l2 smooth (ciliate in Homidia and Sinhomidia ), cephalic groove with scale-like chaetae (absent in Sinhomidia ), manubrium lateral face with long distal mac (absent in Homidia and Sinhomidia ), anterior central region of the Abd. IV with two transverse rows of mac (one in Homidia and Sinhomidia ), and striated dental spines (apparently smooth in Sinhomidia ) ( Figs 8 , 14–15 , 19–20 , 27 , 40–41 ; Tab. 1 ).

Amazhomidia gen. nov. is also similar to Acanthurella and Acanthocyrtus in having 8+8 eyes, scales on dorsal body, Abd. II–IV bothriotrichal formula 2, 3, 2, dental spines present and mucro bidentate with basal spine ( Handschin 1925; Salmon 1964; Zhang et al. 2009). However, Amazhomidia gen. nov. can be distinguished from these two genera by the presence of heavily striate apically pointed scales ( Fig. 2 ) (truncate or pointed in Acanthocyrtus and weakly striate and apically rounded or truncate in Acanthurella ), dental scales absent (present in Acanthurella and Acanthocyrtus ) and body with dense mac (reduced in Acanthurella ). Detailed differences are listed in Table 1 .

The new genus superficially resembles other genera such as Himalanura Baijal, 1958 (Entomobryinae) and Lepidobrya Womersley, 1937 (Willowsiinae) , by having 8+8 eyes, mucro bidentate with basal spine, and body dorsally with ciliated and broadened chaetae (as Himalanura ) (see Salmon 1949; Jordana 2012; Zhang et al. 2014a; Baquero et al. 2014, 2015). The new genus is easily discriminated from the latter by presence of body scales (absent in Himalanura ), unguis with one unpaired tooth (absent in Lepidobrya ) and dental spines (absent in Himalanura and Lepidobrya ).

Amazhomidia gen. nov. with bifurcate prelabral chaetae, only recorded in Pseudodicranocentrus Mari Mutt, 1981 (Heteromurinae), some species of Orchesella Templeton, 1836 (Orchesellinae) ( Mari Mutt 1981, 1984, 1985) and Pseudosinella Schäffer, 1897 (Lepidocyrtinae) , with two rows of mac present on anterior central Abd. IV and bothriotricha with accessory chaetae on Abd. II–IV is a unique case in Entomobryidae , and we erect a new genus for it here.

Figures

FIGURES 1 – 10. Amazhomidia ducke gen nov. sp. nov.: 1, habitus of a fixed specimen in ethanol (lateral view); 2 – 8, different shaped of scales and chaetae: 2, pointed scale, 3, scale-like chaetae of cephalic groove, 4, ciliated chaeta, 5, sens type II on Abd. IV, 6, ciliated microchaeta, 7, accessory chaeta of bothriotricha, 8, dental spine; 9, trochanter chaetotaxy, arrow indicates the extra spine-like chaetae of anterior face; 10, Ant. IV segment, arrow indicates the beginning of annulations. Scale bars: 1 (0.5 mm), 2 – 8 (0.005 mm), 9 (0.05 mm), 10 (0.1 mm).

FIGURES 11 – 17. Amazhomidia ducke gen nov. sp. nov.: 11, habitus (dorsal view); 12, symbols used in detailed chaetotaxy schemes; 13, dorsal cephalic chaetotaxy; 14, chaetotaxy of the clypeus, prelabrum and labrum; 15, apex of Ant. IV; 16, Ant. III organ and associated chaetae and sensilla; 17, chaetotaxy of Ant. I (dorsal view).

FIGURES 18 – 21. Amazhomidia ducke gen nov. sp. nov.: ventral head: 18, labial papillae and proximal chaetae; 19, labial region and proximal chaetae; 20, posterior labial chaetotaxy; 21, maxillary outer lobe and sublobal plate.

FIGURES 22 – 25. Amazhomidia ducke gen nov. sp. nov.: dorsal chaetotaxy: 22, Th. II; 23, Th. III; 24, Abd. I; 25, Abd. II.

FIGURES 26 – 28. Amazhomidia ducke gen nov. sp. nov.: dorsal chaetotaxy: 26, Abd. III; 27, Abd. IV; 28, Abd. V.

FIGURES 29 – 42. Amazhomidia ducke gen nov. sp. nov.: 29, subcoxa I; 30, subcoxa II; 31, subcoxa III; 32, trochanteral organ; 33 – 34, distal tibiotarsus and empodial complex (lateral view): 33, fore leg; 34, hind leg; 35, ventral view of hind empodial complex III; 36, collophore chaetotaxy (lateral view); 37, tenaculum (lateral view); 38, male genital plate and sperm duct; 39, distal manubrium (ventral view); 40, distal manubrium (dorso-lateral view); 41, dens and mucro (lateral view, showing dental spines distribution); 42, distal dens and mucro (lateral view).

Tables

TABLE 1. Comparison of Entomobryidae genera with dorsal body scales and dental spines.

Genera		Amazhomidia	Acanthocyrtus	Acanthurella	Sinhomidia
		gen. nov.	2, 4	1–4	4
Ant. IV annulated		+	+	–	+
Ant. IV bulb		–	+	–	+
Prelabral chaetae		B	S or C	C	S
	M	S	C	C	C
Labial	E	S	C	C	S
chaetae	L1	S	C	C	S
	L2	S	C	C	C
Scale-like chaeta Head ventral		+	–	–	–
Macrochaetotaxy on body		+	+	–	+
Scales shape		pointed	rounded or pointed	rounded or pointed	pointed
Dental scales		–	+	+	–

Notes: (C) ciliated chaeta(e); (S) smooth chaeta(e); (B) bifurcate chaeta(e); (+) present; (–) absent. Reference: (1) Börner 1906; (2) Handschin 1925; (3) Salmon 1964; (4) Zhang et al. 2009.